This invention is generally related to bicycles, and more specifically, to a bicycle having front and rear wheels which are independently steerable.
Bicycles having front and rear wheels which are steerable relative to one another and relative to a main frame have been disclosed in the past and are well known in the art. Disclosures of such bicycles generally teach equal angular displacements of the front and rear wheels relative to the main frame. In most applications, the movement of one wheel causes an equal and opposite movement of the other wheel. The central purpose of this type of bicycle is to enhance performance by decreasing the turning radius of the bicycle.
Great Britain Pat. No. 817,539 to George discloses a bicycle having dependently steered front and rear wheels as discussed above. The George patent teaches a bicycle having two steering heads, one at the front of the bicycle and the other at the rear. The steering heads are provided with hydraulic coupling in order to ensure synchronous, equal, and opposite steering movements of the front and rear wheels. Whereas the type of bicycle which the George patent discloses allegedly enhances bicycle performance, it does not provide a challenging alternative to conventional bicycle riding.
Great Britain Pat. No. 1,433,799 to Belden discloses a bicycle having independently steerable front and rear wheels. The front and rear wheels are independently steered around separate axes of rotation. To operate the Belden bicycle, a rider positions himself astraddle a main frame and upon a seat which is vertically adjustable but otherwise immovably fastened to the main frame. The rider steers the front wheel assembly by manipulating handle bars coupled thereto. The rider can independently steer the rear wheel assembly by lateral podiatric movement of a pedal crank which is coupled by a chain to the rear wheel assembly cog.
Whereas the Belden disclosure alleges to provide a challenging alternative to conventional bicycle riding, it has a number of significant disadvantages. Due to the conventional placement of the pedal crank midway between the front and rear wheel assemblies and directly below the fixed main frame, it is extremely difficult to steer the rear wheel assembly while keeping both feet on the pedal crank. Further, because the seat is immovably mounted upon the main frame and is not in any manner used to aid in steering the rear wheel assembly, it becomes even more difficult to steer the rear wheel assembly while simultaneously rotating the pedal crank to propel the bicycle. Additionally, the axis of rotation for the front and rear wheel assemblies lie in planes which are deviated from a plane which is perependicular to the riding surface. The result is to increase instability of the bicycle and to impede steering the wheel assemblies.
There therefore exists a need to provide a bicycle which has independently steerable front and rear wheels to provide a challenging alternative to conventional bicycle riding while simultaneously being stable and functional.